complexity & change in environment, biomedicine & society

50 whys to look for genes: 25. Congenital traits

Some traits that one is born with may be associated with external factors during gestation, such as exposure to thalidomide. Researchers may, however, in deciding which traits to investigate to look for genes, choose congenital traits in the knowledge that they have been formed without the social interactions or environmental influences that occur after birth. Indeed, even when congenital traits are associated with external factors during gestation, investigating the epigenetic basis of the trait—the way it involves turning on or off a gene—may be fruitful.

Complications

In a field initiated by the epidemiologist David Barker at the University of Southampton, a large number of researchers have been studying associations between nutritional deficits during critical periods in utero and chronic diseases of later life, including heart disease and diabetes. The integration of fetal origins and subsequent influences now takes place under the label of life course epidemiology (Kuh and Ben-Shlomo 2004). [quoted from Taylor 2014, 151)

The associations stand out even after allowing for confounding associations between socioeconomic status, low birth weight, and adult diseases. It appears that, through “gestational programming” of biochemical patterns and cell distribution within organs, disease susceptibility can be inborn, yet with origins that are environmental, not genetic. [quoted from Taylor 2004, 337]